The proposed research for the next project period is a continuation of an analysis of components of primate motor control system. We will continue to study the nature of somatosensory afferent input, including muscle spindle afferents, to the primary motor cortex. In association with this program we will continue a recently initiated study designed to determine the micro-representation of the motor cortex. Also, we will determine the distribution of afferent input within this "micro-representation". Through these studies we hope to better define the input-output relationship of the primary motor cortex. Both anatomic and electrophysiologic methodologies will be employed in these studies.